1. Field of the Invention
The present invention relates to an electric double layer capacitor and aggregation thereof.
2. Description of the Related Art
Capacitors are utilized in backup power supplies and auxiliary power supplies for portable electronic equipment including cell phones, rechargeable devices with solar batteries, and even motor power supplies or regenerative energy devices for so-called hybrid cars. In particular, electric double layer capacitors are suited for use in applications where large capacities are required.
FIG. 15 shows one example of a conventional electric double layer capacitor. This electric double layer capacitor X includes an anode 91 and a cathode 92 having distribution electrodes 91a, 92a made from activated carbon, respectively. A partition wall 93 and an electrolytic solution 94 are arranged between the distribution electrodes 91a, 92a. In the electric double layer capacitor X, so-called electric double layers are generated at interfaces between the electrolytic solution 94 and the distribution electrodes 91a, 92a, on which positive and negative ions are distributed across the interfaces. The electric double layer is used for electric storage. Due to its relatively large electrostatic capacity, the electric double layer capacitor X is suitable for use in the above-mentioned power supply and storage applications.
Recently, however, development of new capacitor applications has started in which capacitors with a relatively large capacity of about 100 μF to 10 F are installed into card-type devices, for example. Although high in capacitance, the electric double layer capacitor X has a structure sealed entirely by a metal cylinder can and does not represent a remarkable improvement in decreased size. Meanwhile, solid electrolytic capacitors are often used in applications requiring miniaturization. These solid electrolytic capacitors, however, do not lend themselves to an increased capacity. Accordingly, there are needs for capacitors that are compact, thin, and suitable for uses in which relatively large capacitances are required.
Another related electric double layer capacitor is disclosed in Japanese Unexamined Patent Publication No. 2003-92234 (see FIG. 1).